PCD bodies, typically films prepared by chemical vapor deposition, are of use as, e.g., heat spreaders, optical components and cutting tools. For many potential applications, however, it will be necessary to be able to appropriately shape an as-produced PCD film.
As is well known to those skilled in the art, PCD has properties that differ substantially from those of conventional (single crystal) diamond. For instance, shaping of a PCD body by polishing typically is impractically slow and inefficient. Indeed, until recently, no convenient and efficient method of removing a significant amount of material from a PCD body was known. See, for instance, W. van Enckevort, Physics World, August 1992, pp. 22.
Recently, some practical methods of removing diamond material from a PCD body were discovered. Common to all these methods is a step of maintaining the relevant surface of a PCD body in intimate contact with a hot (solid, molten or partially molten) metal "etchant". See, for instance, S. Jin et al., Diamond and Related Materials, Vol. 2, (1993), p. 1038; S. Jin et al., Applied Physics Letters, Vol. 60 (16), April 1992, p. 1948; S. Jin et al., Nature, Vol. 362, Apr. 29, 1993, p. 822. See also U.S. Pat. No. 5,328,550, which discloses use of a molten rare earth metal alloy etchant, and U.S. Pat. No. 5,382,314 ('314), which discloses a method of selective diamond removal from a PCD body that involves the use of "etch-retarding" material appropriately interposed between the PCD surface and the (optionally molten) metal "etchant". Co-assigned U.S. patent application Ser. No. 08/368,581, filed Jan. 4, 1995 by J. E. Graebner et al., now U.S. Pat. No. 5,500,157 discloses a method of shaping a PCD body by contacting the surface of the body with an appropriately shaped solid template. The above referenced publications, patents and application are incorporated herein by reference.
Although the method of the '314 patent makes it possible to selectively remove diamond material from a PCD body, the method typically requires one or more thin film deposition steps (typically involving a vacuum deposition process) with delicate thickness control of the etch-retarding material. In view of the commercial importance of shaping PCD bodies, it would be desirable to have available a shaping method that does not require thin film deposition with close thickness control. This application discloses such a method that is, inter alia, adapted for selectively removing material from as-produced PCD film such that, commonly observed, thickness variations and/or film curvature are substantially removed.